Control flow under uncertainty.

—Don Reinertsen

 

Develop on Cadence

Develop on Cadence is a strategy for managing the inherent variability in solution development by making sure important events and activities occur on a regular, predictable schedule. It is an essential method for managing the inherent variability of systems development in a flow-based system.

Develop on cadence helps execute routine development activities on a fast, synchronous cadence—a regular, predictive rhythm of important events.

Cadence makes routine that which can be routine, assuring that important events happen—like system integration, for example. It also lowers the cost of standard events. This is a fundamental premise of SAFe, and its effects can be seen directly on the Big Picture—with the fast cadence of synchronized short Iterations, which are then integrated into larger Program Increments (PIs).


Note: This article is the companion article to Release on Demand.


Details

Cadence and synchronization are the key constructs we use to build our Solution assets. So when we say, “develop on cadence,” we really mean both. Cadence is the use of a regular, predictive development rhythm. Synchronization causes multiple, potentially dependent events to happen at the same time.

Together, cadence and synchronization allow us to make routine that which can be routine, including PI Planning, System and Solution Demos, and system integration, as well as less frequent items, such as adjusting resources and realigning work to teams. These principles (thanks to Don Reinertsen, Principles of Product Development Flow [1]) are so critical to understanding why SAFe works the way it does that we describe some of Reinertsen’s basic principles—along with how SAFe applies them—in Tables 1 and 2.

Principles of Flow: Cadence SAFe Practices
F5: Use a regular cadence to limit the accumulation of variance Planning at regular PI intervals limits variances to a single PI timebox, increasing Agile Release Train (ART) and Solution Train predictability.
F6: Provide sufficient capacity margin to enable cadence In order to reliably meet PI objectives, the Innovation and Planning (IP) iteration has no planned scope and thereby provides a schedule margin. In addition, uncommitted but planned-for stretch goals also provide capacity margin. Together they offer the schedule and scope margin needed to reliably meet PI goals.
F7: Use cadence to make waiting times predictable If a Feature doesn’t make it into a PI, but remains a high priority, its delivery can be scheduled for the next PI (or another scheduled, frequent release). This avoids the temptation to load excess Work in Process (WIP) into the current increment.
F8: Use a regular cadence to enable small batch sizes Short iterations help control the number of Stories in the iteration batch. Feature batch sizes are controlled by short PIs and frequent releases, providing high system predictability and throughput.
F9: Schedule frequent meetings using a predictable cadence PI planning, iteration planning, Product Owner (PO) Sync, backlog refinement, Inspect and Adapt (I&A), architecture discussions, etc., all benefit from frequent meetings. Each meeting needs to process only a small batch of new information. Cadence helps lower the transaction costs of these meetings.

Table 1: Cadence principles applied in SAFe

 

Principles of Flow: Synchronization SAFe Practices
F10: Exploit economies of scale by synchronizing work from multiple projects Individual Agile teams are aligned to common iteration lengths. Work is synchronized by system and solution demos. Portfolio business and Enabler Epics drive common infrastructure and customer utility.
F11: Capacity margin enables synchronization of deliverables Teams plan with stretch objectives, but these can be sacrificed as necessary as plans meet reality.
F12: Use synchronized events to facilitate cross-functional trade-offs Value Stream and program PI events synchronize customer feedback, resource and budget adjustments, mission alignment, I&A improvements, and program review and governance. They also drive collaboration and team building.
F13: To reduce queues, synchronize the batch size and timing of adjacent processes Teams are aligned to common timeboxes and similar batch sizes. The ART and solution system teams support integration on a regular cadence. To facilitate rapid delivery of new ideas, backlogs are kept short and uncommitted.
F14: Apply nested cadence harmonic multiples to synchronize work Teams integrate and evaluate on iteration boundaries (at least). Programs and value streams integrate and evaluate on PI boundaries.

Table 2: Synchronization principles applied in SAFe

Taken together, cadence and synchronization are critical concepts that help us manage the inherent variability in our work. This creates a more reliable, dependable software development and delivery process, one that our key business stakeholders can come to rely on.

But Release on Demand

As we have seen, developing on cadence delivers many benefits. But when it comes to actually releasing value, a different set of rules may apply. Given a reliable stream of PIs, the next and even larger consideration is to understand when and how to actually release all that accumulating value to the end user. As we describe in the Continuous Delivery Pipeline and Release on Demand articles, every ART and solution train needs a strategy for releasing software that suits its development and business context.

Toward Continuous Delivery

For many, the prospect of continuous delivery is desirable. After all, none of us panics when an automatic update becomes available for our phone. Rather, we assume it will deliver value, and we hit that update now button without much thought or concern. Surely there is as much or more software in that phone as in some of our enterprise systems. However, the enterprise world often marches to a different drummer. Perhaps, for security and availability, or for financial (banking, trading), or personal (medical equipment, man-rated systems) criticality, the customer’s operational environment is unsuited for continuous updates of significant new value. Perhaps our enterprise’s development and release capabilities have not advanced to where that is a largely risk-free proposition for our Customers. Perhaps, for whatever reason, it just doesn’t make economic sense.

In addition, systems that support continuous delivery must be designed for continuous delivery. Even then, releasing is not a homogeneous thing. For example, this simple website has multiple release cadences. If, however, we updated the Big Picture every week, the people supporting SAFe with tooling and courseware would think that was a bad approach. However, without the ability to roll out new content (through the blog, guidance, and updates to articles), we’d undermine our goal of continuous value delivery. We couldn’t be as Agile.

In short, you have to design for these things.

In all cases, enterprises that apply SAFe can rest easy knowing that development and releasing are not the same. They can release any quality asset, as needed, to meet business conditions.


Learn More

[1] Reinertsen, Don. Principles of Product Development Flow: Second Generation Lean Product Development. Celeritas Publishing, 2009.

[2] Leffingwell, Dean. Scaling Software Agility: Best Practices for Large Enterprises. Addison-Wesley, 2007, chapter 16.

[3] Leffingwell, Dean. Agile Software Requirements: Lean Requirements Practices for Teams, Programs, and the Enterprise. Addison-Wesley, 2011.

Last update: 13 October, 2017